In an attempt to overcome the reliance upon cans and bottles, packages have recently begun to use flexible, fusible sheet material in forming disposable containers, such as found in U.S. Pat. No. 3,380,646 to Doyen et al and U.S. Pat. No. 4,287,247 to Reil et al. Such containers are problematic, however, in that they have interior crevices in their bottoms and corners which may act as bacterial traps. Furthermore, they must be produced from relatively thick, and therefore expensive, retort material to be capable of standing upright without support. Even if manufactured with such thick material, the packages are typically unstable and must be supported on the shelves of a store by a box or other means. Once purchased and opened, consumers have to empty the contents of the containers into pitchers or other storage means. Also, the flexible containers used to date usually have at least one weld on their interior bottom wall, which is the location of the most pressure from liquid or other packaged products. As a result, there is a structural weakness at the bottom portions of most currently used containers.
The methods employed in producing the currently used flexible containers are complicated in that they require a relatively large number of welding steps, many of which must be performed while the container material is in a vertical orientation. As a result, the apparatus for forming the container is by necessity complicated and expensive.
There exists a need, therefore, for a container which is hermetically sealable, lightweight, and which is flexible so as not to occupy a large volume of space when emptied.
There exists a further need for a flexible container which has no interior crevices, which can be produced from relatively thin material, and which is sturdy, particularly along its bottom.
There also exists a need for a method of producing such a container which provides effective seals yet is simple, quick and inexpensive.